Container structure



Aug. 27, 1963 E. R. HOLMAN CONTAINER STRUCTURE Filed July 17, 1961 EMMETTE R. HoLMA/v IN V EN TOR.

ATTORNEYS United States Patent Ofiice 3,101,839 Patented Aug. 27, 19633,101,839 CONTAINER STRUCTURE Emmette R. Holman, Palos" Verdes Estates,Califi, assignor to Purex Corporation, Ltd., South Gate, Calif., acorporation of California Filed July 17, 1961, Ser. No. 124,696 5Claims. (till. 2062) This invention relates tothe packaging ofchemicals, and is particularly concerned with a container structureembodying novel means to prevent corrosive vapors emanating fromchemicals packaged in the container from coming into contact with, andcorroding or deteriorating the container wall.

In the packaging of corrosive chemicals it is customary practice toinsert thin plastic liners into steel or fiber packing drums. Theseliners isolate the corrosive contents from direct physical contact withthe corrodible outer container. One of the most popular and widely usedtypes of plastic liners for this purpose is the polyethylene liner whichhas an exemplary film thickness of about 0.00s". For many applicationsthe use of such a polyethylene liner has provided adequate protection incommercial practice. However, it has been known that the polyethyleneliner can breathe and that it is permea ble to water vapor. It has alsobeen found that this type of liner is permeable to vapors of the halogenacids such as HCl, l-LBr and HF, and in addition to vapors of ammonia.It also appears to be permeable to other acid and alkaline vapors ofcomparable molecular size, or smaller.

Due to the vapor permeability of such polyethylene liners, it has beenfound in commercial practice that rapid deterioration to completefailure of fiber and also of steel drums often occurs when such drumsare charged with certain chemicals or chemical compositions emitting theabove mentioned corrosive vapors, and the drums stored in an otherwisefavorable environment. Chemicals such as ammonium bifluoride emitcorrosive HF vapors, and mixtures of sodium bisulfate, sulfamic, oxalic,tartaric, and/ or citric acid, and sodium chloride, are notorious foremit-ting corrosive H01 vapors. Such corrosive vapors pass through thepolyethylene liners and attack the fiber or metal wall of the drum.Chemicals such as ammonium bicarbonate, and compositions includingammonium salts such as ammonium sulfate or chloride, mixed withalkalies, release ammonia vapors which are irritating and objectionableparticularly from the odor standpoint. To use liners fabricated ofpolymers having low vapor permeability, and which may include, forexample, neoprene,

and those marketed as Mylar, Thiokol or Hypalon, is pro- I hibitivelyexpensive for use on a disposable basis.

It is an object of this invention to. provide means in containers linedwith vapor permeable plastic materials, for preventing corrosive ornoxious vapors discharged from chemicals packed in such containers fromcoming into contact with and corroding or deteriorating the walls of thecontainer, and from escaping into the atmosphere.

Another object of the invention is the provision of a container, forexample, a steel or fiber drum, having a polyethylene or like vaporpermeable plastic liner, and embodying means for reacting with corrosiveor noxious vapors emitted from the contents of the container and passingthrough such liner, so as to inactivate such vapors and prevent themfrom contacting the walls of said container, or from passing externallytherefrom.

Still another object is the provision of a novel article generally inthe form of a container or drum lined with a vapor permeable,particularly polyethylene, liner.

Other objects and advantages of the invention will appear hereinafter.

The above and other objects are achieved, according to the invention, byproviding a confined barrier zone of a vapor phase between the vaporpermeable liner containing the packaged chemical contents, and the Wallof the container, said vapor phase 'being of a type such as to reactwith and inactivate, e.g. by neutralization, the corrosive Vaporsemanating from the charge of corrosive chemicals within the liner andpassing through such liner into the barrier zone, the reaction productof the two reacting vapors preferably depositing as a solid Within thebarrier zone. Such reaction accordingly inactivates the corrosive vaporsentering the barrier zone through the permeable, e.g. polyethyleneliner, and thus substantially prevents such vapors from reaching thecontainer wall.

To provide the inactivating or neutralizing vapor phase barrier zonenoted above, I incorporate, as a major feat-ure of the invention, aminor amount of a vapor donor substance in the pulverulent solid orliquid form, in the zone between the permeable liner carrying thechemical contents, and the wall of the container. I prefer to use thevapor donor substance in powder or liquid form, and preferably avoidusing such substance in coarse granular or lumpy form, since coarseparticles inserted between said liner and the container wall maypuncture the liner under the load of chemicals packaged within theliner.

In a preferred embodiment I employ two liners of vapor permeable plasticsuch as polyethylene, one such liner being positioned contiguous to orin substantial contact with the wall of the container, the other suchliner being positioned within, or telescoped into, the first mentionedliner. The inner liner is adapted to contain the chemicals or contentsto be packaged. The vapor donor substance is introduced into the zonebetweep the inner and outer liners, constituting the above describedbarrier zone. In this embodiment the corrosive or noxious vapors passingthrough the pores of the inner liner, and entering the barrier zonebetween the liners, reacts with, e.g. is neutralized by, theneutralizing vapors given off by the vapor donor substance in thebarrier zone, causing deposition of a solid reaction product of thevapors in the confined zone between the two liners.

The present of the additional outer liner adjacent to or in contact withthe container wall, although likewise vapor permeable, provides furtherprotection against corrosion of the container wall by any corrosivegases which may not be reacted or neutralized in the barrier zone.However, the main advantage of such outer liner is to prevent contact ofthe deposited reaction product of the corrosive and neutralizing vaporsfrom coming into direct contact with the container Wall, since suchreaction product itself may be of a type which is corrosive, such as achloride or fluoride, e.g. ammonium chloride, as when the corrosive gasis acidic, for example, HCl vapors, and the neutralizing or reacting gasproduced by the vapor donor substance in the barrier zone is alkaline,for example, ammonia. Under these circumstances the reaction product,ammonium chloride, has an acidic reaction, and if brought into directcontact with the wall of the container or drum, would produce corrosionthereof in the case of metal, e.g. steel drum. Where the depositedreaction product of the two gases is a completely neutral substance, thedanger of attack of the container wall by contact thereof with suchsubstance in the barrier zone is minimized, and the outer lineraccordingly may be omitted.

While polyethylene is given as a preferred type of vapor permeable lineremployed in the invention system, the use of other types of vaporpermeable plastic liners can be employed alternatively. Thus, forexample, the newly developed polypropylene sheet plastic, believed to bevapor permeable, can be employed in place of polyethylene. In commercialpractice, fiber drums are often provided with a liner of polyethylenesealed or otherwise integrated into the inner surface of the drum. Suchliner may serve as the outer liner of the preferred form of my containerstructure, the inner liner provided according to the invention servingto form the barrier zone between the two liners.

Although in preferred practice the vapor permeable liners are flexible,vapor permeable rigid liners may be utilized also.

Since the major difficulty in the prior art has been concerned withcorrosion or deterioration of the container brought about by acidicgases such as HCl or HF vapors, the vapor donor substance is generallyone which emits acid neutralizing or alkaline vapors, e.g. ammonia. Apreferred vapor donor substance for this purpose is ammoniumbicarbonate, since it liberates a substantial ammonia vapor pressure.Ammonium carbonate also may be employed, except that the lumpy form ofthe commercial product renders it physically undesirable, due to thedanger of such product puncturing the liner between the barrier zone andthe packaged con-tents under load. However, vapor donor substancesgenerating excessive vapor pressures, e.g. of ammonia, should beavoided, as this will cause the neutralizing gas in the barrier zone topermeate the intermediate liner wall and pass into the packaged contentsheld within said liner, resulting in undesirable rapid spending of thevapor donor substance, and also in simultaneously neutralizing at anundesirable or excessive rate the packaged acidic compound which theliner is intended to preserve. Instead of using ammonia as theneutralizing gas, I may employ amine vapors, e.g. alkyl amines, such astriethylamine, tripropylamine or tributylamine as neutralizing gas, andemploying such amines or their compounds such as the correspondingquaternary hydroxide as vapor donor substances.

-In place of vapor donors emitting acid neutralizing vapors, I canemploy in the barrier zone vapor phase inhibitor substances. These mayinclude, for example, amine salts of carboxylic acids, such as, forexample, cyclohexylamine laurate, oleate or benzoate, and suitablyvolatile nitrites or nitrates.

Where the vapors emanating from the packaged chemicals and passingthrough the liner into the barrier zone are basic, for example, ammonia,the barrier zone may be charged with a vapor donor substance emittingvapors having a base neutralizing or acid reaction to prevent escape ofsuch oxious alkaline vapors. Thus, for example, where the chemicalcontents of the container include ammonium bicarbonate which evolvesirritating ammonia vapors, such vapors can be confined and inactivatedor neutralized in the barrier zone by charging the barrier zone with asmall amount of sodium diacetate, which evolves a substantial vaporpressure of acetic acid.

In preferred practice, the vapors evolved by the vapor donor substancein the barrier zone should have a sufficiently large molecular size thatthe liners employed have minimum permeability to such vapors.

The amount of donor substance introducd into the barrier zone betweenthe inner liner holding the packaged chemical contents and the outerliner or wall of the container, is relatively small. Thus, for example,it has been found that introduction of from about 4 to about 8 ounces ofammonium bicarbonate into the barrier zone of a metal drum having twopolyethylene liners according to the invention, and having 125 lbs. ofpackaged chemical in the inner liner, composed of a mixture of sulfamicacid, sodium bisulfate, ammonium bifluoride and sodium chloride,resulted in a package having a storage life of at least six monthswithout any corrosion or deterioration of the drum. However, in the samepackage, in the absence of the protective barrier zone containing theammonium bicarbonate, the metal container will show substantialcorrosion within 24 hours storage time.

T he invention is further illustrated by the description below of apreferred embodiment, taken in connection with the accompanying drawingwherein:

FIG. 1 illustrates a drum in the process of being charged, embodying theinvention principles; and

FIG. 2 shows the drum of FIG. 1 after it has been filled and sealed.

Referring to FIGS. 1 and 2, numeral 10 represents a conventional form ofdrum, which may be constructed of steel or fiber. An outer liner 12 inthe form of a polyethylene bag is placed in the drum around the interiorwall thereof, and the upper end 13 of the bag is folded down over theupper edge of the drum, as seen in FIG. 1. A small amount of vapor donorsubstance, e.g. ammonium bicarbonate, indicated at 14, is thendistributed over the liner 12 at the bottom of the drum, and a secondsimilar liner 16, in the form of a polyethylene bag is telescoped intothe outer bag 12 in the drum, leaving an annular space 18 between theside walls of the two bags or liners. The upper end 20 of the inner bag16 extends upwardly exteriorly of the upper end of the drum and isconnected to a bag filling apparatus (not shown). The inner bag 16 isthen partially filled, say about one fourth to one third full, withchemicals to be packaged, e.g. a composition including ammoniumbifiuoride, as indicated at 22, and additional vapor donor substance 14is distributed in the annular space 18 around the contends 22 partiallyfilling bag 16. This filling process is continued by alternatelycharging additional quantities of chemical into bag 16 and distributingvapor donor substance 14 into the annulus 18 until the bag 16 iscompletely filled or filled to the desired amount, with vapor donorsubstance 14 completely surrounding the sides of bag 16 in the barrierzone 18 between the two bags, up to the top of bag 16, or to a heightcoextensive with the height of the charge of packaged material in liner16.

The upper end of bag 16 is then tied in any suitable manner as indicatedat 24, and additional vapor donor substance 14 is then distributed overthe top of inner bag 16, and the upper end of bag 12 is then tied asindicated at 26. It is thus seen in FIG. 2 that the inner bag 16containing the packaged chemical contents indicated at 22, is entirelysurrounded by a barrier zone between bags 12 and 16, containing arelatively minor amount of vapor donor substance 14. The top 28 is thenplaced on the drum.

Thus, acid vapors emitted from the chemical 22 contained within bag 16,and passing through the vapor permeable polyethylene liner or bag 16into the barrier zone 18, are caused to react with the ammonia liberatedby the ammonium bicarbonate in such zone, forming, for example, ammoniumfluoride, which deposits as a solid in the barrier zone between liners12 and 16, out of contact with the wall of drum 10, preventingdeterioration of the drum. The resulting package has a storage life ofseveral months without any material deterioration taking place.

From the foregoing, it is seen that the invention provides a containeror package designed particularly for packing chemical substances, andincorporating a simple novel means for preventing corrosive and/ornoxious vapors emanating from the contents of such package, fromattacking the container walls, and preventing leakage of such corrosiveand/or noxious vapors from said container to the surrounding atmosphere.

While I have described particular embodiments of my invention forpurposes of illustration, it should be understood that variousmodifications and adaptations thereof may be made within the spirit ofthe invention as set forth in the appended claims.

I claim:

.1. A container adapted for packaging materials normally emittingcorrosive vapors, comprising a drum having an outer substantially rigidwall formed of a material normally subject to corrosion by saidcorrosive vapors, an outer liner positioned in said drum contiguous tosaid outer Wall, an inner liner telescoped within said outer liner butspaced therefrom to form a confined barrier zone between said inner andouter liners, said inner and outer liners being formed of a flexiblechemically resistant synthetic resin permeable to vapors, and a smallamount of a powdered solid vapor donor substance distributed in saidbarrier zone, said substance being capable of emitting, and having avapor pressure sufficient to emit, vapors of a type to neutralize anycorrosive vapors passing through said inner into said barrier zone.

2. A container as defined in claim 1 wherein said liners are composed ofpolyethylene.

3. A container adapted for packaging materials normally emittingcorrosive and/ or noxious vapors, comprising a drum having an outersubstantially rigid wall, an outer liner positioned in said drumcontiguous to said outer Wall, an inner liner telescoped Within saidouter liner but spaced therefrom to form a confined barrier zone betweensaid inner and outer liners, said inner and outer liners being formed ofa flexible chemically resistant synthetic resin permeable to vapors, anda small amount of a vapor donor substance distributed in said barrierzone, said substance being in powdered solid form and capable ofemitting vapors of a type to inactivate any of said first mentionedvapors passing through said inner liner into said barrier zone, andforming a solid reaction product in said zone.

4. A package comprising a drum having an outer substantially rigid wall,an outer liner positioned in said drum contiguous to said outer wall, aninner liner telescoped within said outer liner but spaced therefrom toform a confined barrier zone between said inner and outer liners, saidinner and outer liners being formed of a flexible chemically resistantsynthetic resin permeable to vapors, a material contained in said innerliner and normally emitting corrosive and/or noxious vapors, and whichpass through said inner liner and into said barrier zone, and a smallamount of a substance distributed in said barrier zone, said substancebeing in powdered solid form and normally emitting vapors of a type toreact with and inactivate said first mentioned vapors passing throughsaid inner liner into said zone.

5. A package comprising a drum having an outer substantially rigid wallformed of a material normally subject to corrosion by acidic vapors, anouter liner positioned in said drum contiguous to said outer wall, aninner liner telescoped within said outer liner but spaced therefrom toform a confined barrier zone between said inner and outer liners, saidinner and outer liners being formed of a flexible chemically resistantsynthetic resin permeable to vapors, a solid powdered chemical materialcontained in said inner liner and normally emitting acidic vaporscorrosive to said outer wall, and which pass through said inner linerand into said barrier zone, and a small amount of a substancedistributed in said barrier zone, said substance being in powdered solidform and normally emitting alkaline vapors of a type to react with andinactivate said corrosive acidic vapors passing through said inner linerinto said zone, and forming a solid reaction product in said zone, saidsubstance being present in amount of about 4 to about 8 ounces per lbs.of said material.

References Cited in the file of this patent UNITED STATES PATENTS848,960 Braun Apr. 2, 1907 1,042,801 Kitsee Oct. 29, 1912 1,408,757Metzger Mar. 7, 1922 2,326,968 Pomeroy Aug. 17, 1943 2,451,523 Walb Oct.19, 1948 2,748,673 Winstead June 5, 1956

5. A PACKAGE COMPRISING A DRUM HAVING AN OUTER SUBSTANTIALLY RIGID WALLFORMED OF A MATERIAL NORMALLY SUBJECT TO CORROSION BY ACIDIC VAPORS, ANOUTER LINER POSITIONED IN SAID DRUM CONTIGUOUS TO SAID OUTER WALL, ANINNER LINE TELESCOPED WITHIN SAID OUTER LINER BUT SPACED THEREFROM TOFORM A CONFINED BARRIER ZONE BETWEEN SAID INNER AND OUTER LINERS, SAIDINNER AND OUTER LINERS BEING FORMED OF A FLEXIBLE CHEMICALLY RESISTANTSYNTHETIC RESIN